Good enough. The h-pawn is ready to move to h5, destroying the king's position. The bishop can go to f3, attacking the pawn on d5.
28... b6b3 Trying at least to attack the the a4-pawn, but the queen is far from the kingside and the absence is felt. 29. h6f4  29... b3a4  30. g1g2 A prophylactic move. 30... c6c5 